Spatial–Temporal Analyses of Surface Coal Mining Dominated Land Degradation in Holingol, Inner Mongolia

Surface coal mining and urbanization, as well as crop-based agriculture, have resulted in accelerated degradation and desertification of grasslands in the Holingol region, Inner Mongolia Autonomous Region, over the last three decades. The purpose of this study was to investigate the spatial–temporal changes of land cover due to the surface coal-mining activities in the Holingol region from 1978 to 2011. In this study, we used the subspace method to apply land-cover classification schemes to Landsat archival images from 1978, 1988, 1999, and 2011. We then used the grid square method to investigate spatial–temporal land-cover changes during the period of 1978–2011. The results show that both surface coal mining and urban areas have increased dramatically. This expansion was accompanied by considerable loss of grassland and wetland. Grid-cell-based spatial–temporal analysis showed that urban/bare expansion had a strong negative correlation with grassland change ( $-{\bf 0.67}$ ), coal-mining area expansion had a negative correlation with grassland change ( $-{\bf 0.29}$ ), and coal-mining area expansion was positively correlated with urban/bare expansion (0.21). Furthermore, the correlation coefficients of land-cover categories for three time intervals between 1978 and 2011 (1978–1988, 1988–1999, and 1999–2011) showed that there was almost no correlation between grassland and coal-mining area in 1978–1988 and 1988–1999, but the correlation coefficient became negative ( $-{\bf 0.21}$ ) in 1999–2011.